Cabin pressure during cruise for some airplanes may be, for example but without limitation, 6000 ft. or 8000 ft. above sea level. For a new airplane program, a ground-based mock-up of a section of a cabin may be built to test, design and optimize, for example, air diffusers even though air density at sea level is substantially different from that in an altitude at 6000 ft, 8000 ft, or 10000 ft. An effect of ambient pressure on air flow patterns in cabins and cargo holds are significant. Therefore, optimized in-cabin air flow pattern based on the ground-based mock-up tests may not perform the same as in flight testing during a cruise stage.
An altitude chamber for testing some aircraft may be too small to accommodate a full-scale cabin mock-up, and thus cannot be adequately applicable to a small scale cabin model with scaled down air diffusers. For these aircraft, a database needs to be built for high altitude/depressurized conditions to obtain Federal Aviation Administration (FAA) certification. Due to lack of such a data set, one may need to compromise accuracy of engineering analysis particularly by using likely unrealistic ground data to extrapolate for airplanes at high altitude conditions. It is very costly to have an altitude chamber which can be used for a section of a full scale cabin or cargo compartment mock-up due to energy consumption for such a facility. There are currently only a few such facilities in the world.